1. Field of the Invention
This invention relates to a microencapsulation technique and more specifically to a method of encapsulating pesticides and insect growth regulators.
2. State of the Art
Many microencapsulation techniques are known in the art and many of them are described in "Microcapsules and Microencapsulation Techniques," M. H. Gutcho, Noyes Data Corporation, N.J., 1976. The known art which is closest to the subject invention is the following:
1. U.S. Pat. No. 3,523,906. The substance to be encapsulated is emulsified in a solution of a polymeric material in solvent and the solvent is removed by evaporation. PA1 2. U.S. Pat. No. 3,914,402. An ophthalmic antibiotic and an ophthalmic steroid are encapsulated with polylactic acid. PA1 3. U.S. Pat. No. 3,909,444. The material to be encapsulated is dispersed in a mixture of solvent, polymeric capsule wall material, and polyethylene, the mixture heated and then slowly cooled during the cource of which capsules are formed. PA1 4. U.S. Pat. No. 3,557,279. Ethylcellulose, polyethylene granules and indomethacin are dispersed in cyclohexane and heated. The mixture is then allowed to cool during which the ethylcellulose lost solvent and developed into solid encapsulating walls.